Originally Posted by USATraveler
I have a 2012 Adventure with a rear bathroom, I have had it in for warranty work to try and correct this problem to no success. If you open one of the drawers to the cabinet or stand by the stool, there is a strong black tank order. Has anyone else had this problem and if so how did you correct it?
It sounds like a stuck vent check valve. Some mfgs install a vent stack in a cabinet near the stool, usually a foot or so off the floor. On top of that pipe is a check valve. When you dump the tank, it allows air to flow into the tank to decrease vacuum. If this valve sticks open, then you will get that odor. There are other causes of course, but I would check that first.